Fuel oil composition



3,145,079 FUEL GIL CGIViPOfiTHBN John H. Udelhofen, Cahiniet City, TIL,assignor to Satandard ()il Company, Chicago, EL, a corporation ofIndiana No Drawing. Filed Sept. 13, 1960, Ser. No. 55,731 4 Claims. (Ci.44-63) This invention relates to novel corrosion and/or rust inhibitorsparticularly adapted for use in preventing corrosion of metalsespecially iron, steel and ferrous alloys by liquids containingcorrosive compounds such as, for example, petroleum fuel oil and to themethod of preventing such corrosion.

The rusting of steel used in the transportation and storage of petroleumfuel oils has always presented a serious problem. The presence ofsediment and rust as a result of corrosion and the carry-over of thesediment into the fuel burning installations presents a seriousoperating problem. In addition to the possibility of storage tankrusting through with the consequent loss of fuel oil, there is theadditional danger that the furnace filters and failure of the heatingsystem.

The problem of corrosion or rusting is associated with the presence ofmoisture in the oil products caused by entrainment, condensation andsolution. In most cases, the problem is accentuated by the presence of aseparate water phase. Thus, in the storage and bulk shipment of fueloil, it is common practice to maintain a water layer as tank bottoms.Even where a separate water layer is not maintained as tank bottoms, aseparate water phase may be formed by repeated condensation of moistureassociated with tank breathing or the repeated expansion and contractionof the bulk due to temperature changes unless special precautions aretaken. Complete protection against rusting, therefore, requires acorrosion inhibitor which is effective in both the oil and water phase.

It is an object of the present invention to provide a corrosion and/ orrust inhibitor adapted for use in preventing the corrosion and/orrusting of metals by liquids containing corrosive compounds associatedwith oleaginous materials such as petroleum fuel oils. It is a furtherobject of this invention to provide a normally liquid nonlubricatinghydrocarbon fuel oil composition having improved rust inhibitingproperties for the protection of metal surfaces of oil storage and/orhandling equipment whether metal surfaces be exposed to the oil or tothe water phase. Other objects and advantages of the invention willbecome apparent from the following description thereof.

I have now discovered certain new corrosion inhibitors which findutility as inhibitors for fuel oils. The corrosion inhibitor is an imideprepared by reacting propylene diamine with polybasic aromatic acid. Thecorrosion inhibitor of the present invention is an imide represented bythe formula C coon NCH2CH2 2N placed in a reactor.

$,M,79 Patented Aug. 25, 1964 wherein R is C1248 alkyl radical and R isa member of the group consisting of H and a C alkyl radical.

The alkyl groups of the above formula are preferably hydrocarbon alkylgroups. The preferable hydrocarbon groups are those groups having fromabout 12 carbon atoms to about 18 carbon atoms such as, for example,those derived from higher fatty acids, e.g., lauryl, oleyl, linoleyl,tallow, soybean, coco, stearyl, palmityl, myristyl and the like.

- The corrosion inhibitors of this invention may be used to form a fueloil composition containing a major proportion of a distillate fuel oiland a small or minor amount of the corrosion inhibitor. Such distillatefuel oil compositions may comprise a distillate fuel oil containing fromabout 0.0001 to about 5 weight percent and preferably from about 0.0001to about 0.05 weight percent of the corrosion inhibitor. The corrosioninhibitor may also be formulated as an addition agent concentrate in asuitable organic solvent as more particularly described below. Thisconcentrate may be used by further dilution with the distillate fuel oilto form the distillate fuel oil composition. The corrosion inhibitors ofthe present invention are advantageously oil-soluble.

The corrosion inhibitors of this present invention may be prepared byreacting the corresponding propylene diamine in the presence of inertsolvent with polybasic aromatic acid. The reaction may be carried out inthe presence of a solvent such as benzene, ethanol, n-butanol,isobutanol, xylene, etc. A acceptable temperature for the reaction maybe in the range of from about F. to about 200 F. although higher orlower temperatures may be used.

The following procedures illustrate the method of preparing thecorrosion inhibitor of the invention.

PROCEDURE A A mixture of 5.94 g. of N,N ditallow 1,3 propylene diamine,1.92 g. of trimellitic anhydride, and 50 ml. of xylene were placed in areactor. The reactor was heated to the reflux temperature of Xylene andmaintained at this temperature for a period of 8 hours after which 0.20ml. of water was recovered. A total of 6.5 g. of product having thefollowing formula was recovered:

PROCEDURE B A mixture of 20 g. of N-tallow 1,3-propylene diamine, 9.6 g.of trimellitic anhydride, and 250 ml. of Xylene were The reactor washeated to the reflux temperature of xylene after which 0.90 ml. of waterwas recovered. A total of 29 g. of product having the following formulawas recovered:

The corrosion inhibitors defined herein, such as those prepared asdescribed above as well as those set forth in the above examples areusable in minor amounts from about 0.0001 to about 5 weight percent andpreferably from about 0.001 to about 0.05 weight percent in distillatefuel oils.

The distillate fuel oil may belvirgin or cracked petroleum distillatefuel oil. 'The fuel oil may boil in the range of from about 200 to about750 F., and preferably in the range of 350 to 650 F. The distillate fueloil may contain or consist of cracked-components such as, for example,those derived from cycle oils or cycle oil cuts boiling heavier thangasoline, usually in the range of from about 450 to 750 F. and may bederived by catalytic or thermal cracking. The distillate oil may containother components such as addition agents used for a particular functionsuch as, for example, pour point depressants, combustion improvers, orthe like.

The distillate fuel oil is preferably a heating oil in which thecorrosion inhibitors of this invention are used in accordance herewith.These oils are intended for use by burning to obtain heat such as isintended for furnace or heater fuel use as opposed to internalcombustion engine fuel wherein the explosiveness of the fuel in acombustion chamber is of prime importance. Examples of such heating oilsare a heavy industrial residual fuel (e.g.,-Bunker C), a heater oilfraction, a gas oil, a furnace oil, kerosene, or any other light oilintended for furnace or heater fuel use.

The rust inhibiting properties of the above described compositions wereevaluated by the following test:

INDIANA CONDUCTOMETRIC TEST (STATIC) This test, which quantitativelymeasures corrosion rates, depends upon the measurement of the change inelectrical resistance of a steel test strip immersed in the corrosivemedium. The change in resistance is simply related to the decrease inthe thickness of the test specimen caused by corrosion. In the test,specimen holders are designed to make electrical connections to twosteel strips suspended in large glass test tubes. A mixture is preparedusing six parts of hydrocarbon oil containing the rust inhibitor andfour parts double distilled water. The corrosion test strips are firstimmersed in the oil containing the rust inhibitor for a period ofone-half hour and subsequently suspended in the mixture such thatapproximately one-half of the specimen is above the oil-water interfaceand the remaining half of the specimen is below the oil-water interface.The strips are maintained in the mixture for a period of 24 hours at atemperature of 25 C. The corrosion rates are calculated on a quantativebasis from the observed change in electrical resistance comparing thespecimen from the inhibited mixture with a specimen run under the sameconditions in an uninhibited mixture.

The data obtained by subjecting theproducts of this invention to theabove test are tabulated in the following table and demonstrate theeffectiveness of the herein described products in inhibiting rust infuel oil compositions.

2 Virgin gas 011. water.

do 92 10- 'M HCL. 93 97. 5

Heater oil Gasoliue The corrosion inhibitors of the present inventionmay, for convenience, be prepared as an addition agent concentrate.Accordingly, the corrosion inhibitor is prepared in or dissolved in asuitable organic solvent therefor in amounts greater than 10% andpreferably from'about 25% to about 65%. The solvent, in suchconcentrate, may conveniently be present in amounts of from about 35% toabout 75%. The organic solvent preferably boils within the range of fromabout 100 F. to about 700 F. For the preferred heating oil use, theorganic solvents may advantageously be hydrocarbon solvents, forexample, petroleum, petroleum fractions, such as naphtha, heater oil,mineral spirits and the like, because of their clean burning properties.The solvents selected should, of course, be selected with regards tobeneficial or adverse effects it may have on the ultimate fuel oilcompo- I sition. Thus, the solvent should preferably burn with- 'outleaving a residue and should be non-corrosive with regard to metal, andespecially ferrous metals. Other desirable properties are obvious fromthe intended use of the solvent.

The terms coco, soybeans, tallow, and the like as used herein denotethat the group so identified is derive/1 from a particular source. Thecoco groups are derived from mixtures of coco fatty acids; the soybeangroups are derived from soybean fatty acids; the tallow groups arederived from tallow fatty acids. Such coco, soybean and tallow fattyacids are derived from coconut, soybean and tallow oils and are marketedcommercially. Each such group is usually a mixture of carbon chainsdiffering slightly in length and/or configuration. For example, thetallow groups are a mixture of C to C groups predominating in stearyland palmityl groups.

a, at

' The groups are well known in the additive art.

Wherever percentages are given herein, weight percentages are intendedunless otherwise indicated.

It is evident from the foregoing that I have provided new and usefulcorrosion inhibitors for distillate fuel oils and particularly indistillate heating oils.

I claim:

1. A distillate fuel oil composition comprising a major proportion of ahydrocarbon oil fraction in the fuel oil wherein R is a C1248 alkylradical and R is a member of the group consisting of H and a C alkylradical.

2. A corrosion inhibitor concentrate for use in a distillate fuel oilcomprising from about 35% to about 75% by weight of an organic solventand from about 25% to 5 6 about 65% by weight of an imide having theformula 4. A fuel oil composition comprising a major proportion of ahydrocarbon oil fraction in the fuel oil disstillation range and fromabout 0.0001 to about 5.0%

by weight of an irnide having the formula COOH 0 NCHZCHZCHZN II 0 R1 ROOOH ll NcmomomN 10 R1 wherein R is a C1248 alkyl radical and R is amember of the group consisting of H and a C alkyl radical. 0

3. A fuel oil composition comprising a major proh R C k 1 a1 d R portionof a hydrocarbon oil fraction in the fuel oil dis- W erem 1s a a1 Ia 1Can 1 1S ydmgen tillation range and from about 0.0001 to about 5.0% by 15References Clted 111 the file of thls Patent Weight of an imide havingthe formula UNITED STATES PATENTS 0 1,908,705 Jaeger May 16, 1933 ll2,604,451 Rocchini July 22, 1952 R 2,699,427 Smith et a1 Jan. 11, 1955COOH 2,816,897 Wolf Dec. 17, 1957 H 3,056,832 Stromberg Oct. 2, 1962 7;R1 OTHER REFERENCES New Reactions of Fatty Amines Show Promise for ManyApplications, article by McCorkle in Chemical and wherein 1 and 2 areeach C12-18 alkyl Tadlcal- Engineering News, August 17, 1953, pages3354-3355.

1. A DISTILLATE FUEL OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A HYDROCARBON OIL FRACTION IN THE FUEL OIL DISTILLATION RANGE AND FROM ABOUT 0.0001 TO ABOUT 5.0% BY WEIGHT OF AN IMIDE HAVING THE FORMULA 